1. Field of the Invention
The present invention relates, generally, to electronic percussion instruments and, in preferred embodiments, to electronic percussion instruments having the capability of sensing and determining the point of impact and the impact pressure on a pad, and processing sensor information to control output sounds in conformance with the point of impact and impact pressure.
2. Description of Related Art
In electronic percussion instruments of the past, the location at which the surface of the pad has been struck with such things as a stick (hereafter, referred to as xe2x80x9cthe location of the point of impactxe2x80x9d) is detected and the control each of the various parameters and such of the musical tone that is generated by the sound source is carried out in conformance with the location of the point of impact and the striking strength.
Examples of prior methods for the detection of the location of the point of impact are described below.
Method 1: This is a method in which, for example, one piezoelectric device is arranged on the pad case as a vibration sensor with which the striking of the impact surface is detected, the vibrations that have been transmitted to the case when the impact surface has been struck are detected by the piezoelectric device, the frequency characteristics of the detection output signal are analyzed by the processor (CPU) and the location of the point of impact is determined based on the fact that the frequency characteristics will be different depending on the variation in the transmission path in accordance with the location of the point of impact.
Method 2: This is a method in which two piezoelectric devices are arranged in separate locations on the pad case and since, due to the fact that the paths along which the striking vibrations reach said two piezoelectric devices will differ in conformance with the location of the point of impact of the striking and the size of the output values of the two piezoelectric devices will each be different, the location of the point of impact is determined by a comparison of the output values of the two piezoelectric devices.
Method 3: This is a method in which the impact surface of the pad is divided virtually into a multiple number of regions, a pressure sensitive device is established for each divided region so that they act mutually independently and, when the impact surface is struck, by means of the output of a detection signal from any of the multiple number of pressure sensitive devices, the region of the pressure sensitive device for which there has been an output is determined to be the location of the point of impact.
The determination of the location of the point of impact is possible with the use of any of the methods discussed above. However, each of the methods has problems such as those described below.
In Method 1, for each time there is a striking, the frequency characteristics of the output signal of the piezoelectric device are analyzed by the processor. However, since the complicated calculations for this analysis must be carried out instantaneously, there is a great load placed on the processor and there is a danger that other internal processing will be delayed.
In Method 2, there is no way that the method can be applied without the detection of the location of the point of impact by the second piezoelectric device and the fact that two of the same kind of sensor device (the piezoelectric device) must be specially established on a single pad may cause much waste with respect to cost.
In Method 3, since the pad is divided into a multiple number of regions by a multiple number of pressure sensitive devices, which region has been struck can be ascertained, however, it is not possible to know in greater detail what specific area within the region has been struck. If it is designed so that the number of divisions of the previously mentioned regions are made more numerous and smaller regions are produced, it is possible technologically to detect the location of the point of impact virtually without gradations but, in actuality, since the number of wires becomes large and complicated and the cost becomes high, it is not desirable.
Therefore, it is an advantage of embodiments of the present invention to provide an apparatus and method for detecting the point of impact on an electronic percussion instrument with a small number of sensors rather than a large array of sensors, which provides the added advantages of reducing the processing load on the processor that receives output values from the sensors and minimizing device complexity.
It is a further advantage of embodiments of the present invention to provide an apparatus and method for controlling the musical tone in conformance with the point of impact, and for controlling different musical tone parameters using the output values of multiple sensors.
These and other advantages are accomplished according to an apparatus for detecting and processing impacts to an electronic percussion instrument. The apparatus includes a pad for being impacted with an impact pressure at an impact point, and several sensors. One sensor is located in close proximity to the pad for producing a first output value corresponding to the impact pressure, and another sensor located in close proximity to the pad for producing a second output value corresponding to the impact point and the impact pressure. A processor determines a computed impact point from the first and second output values, and controls output sound in conformance with the computed impact point.
These and other objects, features, and advantages of embodiments of the invention will be apparent to those skilled in the art from the following detailed description of embodiments of the invention, when read with the drawings and appended claims.